Hello from the Wix DevRel Team!
This sounds like it should be possible with Velo and JavaScript. You would add a function that is called onMouseIn() when you hover over your button, and then change the color , backgroundColor , and any other details you wish to modify to be consistent with the rest of the menu. You probably also want to write a function that makes the “Programm” menu item brown with white text when the user is on any of the pages nested within that submenu. You should be able to accomplish this with the Page API.
Hope this helps!
Rob